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Aug. 18,1931. F. w. BERNAU OW MINERAL KEY LOCKING IECHANISI 9Sheets-Sheet 1 Filed Sept. 13, 1926 Aug. 18, 1931.

Filed Sept. 13, 1925 9 Sheets-Sheet 2 Aug. 18, 1931.

7 F. W. BERNAU OVERDHAFT NUMERAL KEY LOCKING MECHANISM 9 Sheets-Sheet 3Filed Sept. 15, 1926 Aug. 18, 1931.

QKING IBCHANISI 9 Sheets-Sheet 4 Filed Sept. 115 1926 Aug. 18, 1931. w,BEQNAU 1,819,066

OVERDRIKQT RUIERAL KEY LOOKING IECBANISI Filed Sept 13, 1925 9Sheets-Sheet 5 Aug. 18, 1931. F. w. BERNAU OVERDRAFT NUMERAL KEY LOCKINGMECHANISM 9 Sheets-Sheet 7 Filed Sept. 13, 192

Aug. 18, 1931;

I P. w. BERNAU ovnqljm mam. m LOOKING momma Filed SQ pt iS, 1 92s 9'Sheets-Sheet 8 k2 w3uw mu g xuk $29k QR.

new Aug. 18,1931 M i 7 v 1,819,066

UNITED STA ES PATENT emcernannmcx w. as figer gimme. new mm, more: re mmm6 TYPEWRITEB m or mum, new mm. a conronarron or m when k ovamnnm m memeApplication me seawater is, me. mm ll'o. 135,141.;

This invention relates to an overdreft ated by the accumulator to lockthe numeral numeral key locking mechanism "for calcukeys ofthe keyboardand when an atmnpt lating machines: is made thereafter to depress theraised nu- In my Patent 1,508,267 September 9, 1924, meral keys for thepurpose of further eddithere is set forth a total and subtmal key tionor subtraction, the locked condition of locking mechanism which isautomatically said keys constitutes a signal, notifying the operatedwhen an overdraft occurs in the operator of the overdraft condition.

accumulator, and in my Patent No. 1,731,701 It then becomes 11 w: 1 ryfor the operator dated October 15, 1929 disclosure ismade to releasethelockin means which have ren 0 of locking meansfor the starting bar ordered the numeral eys inoperative. This operating means of the machine.canbe accomplished by dep the add- ;'I'he,present invention has for. itsobject mg and starting her and causing the therovision of improved meansoperated machine to thite cycle of I automatically when anoverdraftcondition trons, the adding into mom It exists in theaccmnulator of a celculat cumuhtor e amount represented by the machinethereupon to lock the unite keysconstitutingtheovernumeral keys and tolock the pmvscusly dedraft. pressed keys which have caused the over- MyImprovements are illustrated in condraft o that release of said keysmnnot be nectmn with so much of theEllis machine so had until e;-operatoireleases the locking as. will afford erlear understanding of themeans. construction andmode of operation thereof, My numeral key lockingmechanism me but reference into/fie bid to the Ellis Patbe used inconjunction with the total an entslios. 1,197,276,!1d 1308M, andtomysubtotal key overdraft locki mechanism Patent 1,508,267 fonillustrationof those of my Patent N 0. 1,508,267, 0B,, which, 110W beeomewellbaroverdraft locking mechanism; Patknow to the art, require no detailillustn 1 ent N 0. 1,731,701, or, in connectidnlgi Both tion' of saidmechanisms, or, it may beamed on p In the accompan ing drawings: acalculatin machine where ofsaid' Figure 1,13 0 (Ltul rear elevation, thelocking mec anisms are present. V When referring to a calc'ul p Fig. 2,is a similar view, the she chine, it is to be understood thatI ref-jbeen turned; erence to an adding, or subtracting nFigsB, is a section online 8-3, Fig. 1; machine of any character because, While the is asection on line 4-4, 2; as present im rovements have been devifled ar-'5 mprises d t il ia f th 1tic ularly or usle i111 cilllnnectitgi with,tlzef fig; d.%t isprintingcacuat gmac inensm 9 i s the pge g g to g l qNo. 7, ingig fg etgmprmes detail views of the lock eptem 1916 an 0.1,203,888 10mm Q 40 her 7, 1916, and other patents the m i mgfgfi gififthe iW operating shaft being in normal fgoizltion;

Ems type ii,gizfim"g,i Fit;: 7, is e view like in .2, but with eer- Irovements may be a I t atin machines without departing the t 0mm, bangprinc ples'of the invention. to black the eontmlhnl .8

" In a calculating machine provided with QWP P my improvements, theoperator maymntinue F 8- $31 View like}? 8- the "W to use the keyboarduntil an overdraft -or e g retm opq e P 9?" negative amount isrepresented on the acthe locking trigger remaining in position tocumulator. When an overdraft condition ocprevent restoration of thecontrolling curs, the mechanism is automatically oper- Fig. this: viewshowing tbe qckmg trigger in normal position, as when no overdraftexists in the machine;

Fig. 10, is a similar view, illustrating how the locking trigger isoperated to prevent restoration of the controlling bar when an overdraftoccurs.

Figs. 11 and 12 are, respectively, front and rear elevations of thekeyboard section of the machine of the Ellis Patent No. 1,197,276showing how my improvements co-operate therewith;

Fig. 13 is a side elevation of the numeral key latch and lock and therack lock thereof;

Fig. 14 is a vertical center section of the adding and subtractingmachine of the Ellis Patent 1,203,863, the parts being in normalposition;

Fig. 15 is a detail elevation of the numeral key release mechanismthereof, the parts bemg normal for adding;

Fig. 16 is a detail view showing the means by which the numeral keyrelease bar is operated;

Fig. 17 is an elevation of the left hand side of the Ellis machine asdisclosed in the Bernau Patent No. 1,508,267, showing the subtractingkey in depressed position, the mechanism for controlling the adding andsubtracting accumulator, and the overdraft locks for the total andsubtracting keys, the latter being in normal position;

Fig. 18 is a perspective skeleton view of the Ellis machine asillustrated in the Bernau Patent No. 1,508,267 the side frames being indotted lines, showing the overdraft mechanism and operative connectionsto the locks for the total and sub-total keys, and the decimal slide,the parts being in normal position;

Fig. 19 is a partly sectional, partly elevational, detail view of theoverdraft mechanism as set for carrying on a subtracting operation,before an overdraft has taken place; and

Fig. 20 is a similar view showing the positions of the parts after anoverdraft has taken place.

Reference is to be had more particularly to Figs. 5 to 14 inclusive and51 of the Ellis Patent 1,197,276, and the description in said patentrelating thereto for a detailed disclosure of numeral keys and theirlatches and manner of operation for those parts of the numeral keyboardand its accessories which are not shown in detail in the accompanyingdrawings.

Reference is to be made to the disclosures of the Ellis Patent1,203,863, for the details of the construction and mode of operation ofthe accumulator, and to my Patent No. 1,508,267, more particularly toFigs. 1, 8, 9, 10, 11, 12, and 13 for a complete disclosure of theoverdraft mechanism which is automatically operated by the accumulatorwhen an overdraft occurs.

.ing key stems of the The mechanisms shown and described in thesepatents and, more particularly, the mechanisms heretofore specificallyidentified by the reference to the views or figures thereof afford aclear understanding of how the present improvements for locking thenumeral keys may be operated when an overdraft occurs and released bythe operator after they have been locked.

Referring to Fig. 14, the machine has a rack R for each bank or row ofnumeral keys, mounted to slide on two slotted cross bars K and R Themovement of each rack R backward and forward is limited for the purposeof addition and subtraction by the stops K secured to the verticalslidkeys, K K K etc. to K The key, K does not limit the travel of therack, but permits it to go its full stroke which is limited by thedownward projections at the ends of that part of R which slides in thegroove in the bar K These stops, K are so arranged that they engagesteps on the upper edge of the rack R and these steps and the stops, Kare arranged vernier fashion so that from the first step to the firststop, K on the key stem K, the rack R could move a distance of onetooth, while stop K on the second key K would permit the rack R to movea distance of two teeth and the stop K on the key stem of K would permitthe rack to move a distance of three teeth, etc., up to K, which servesthe purpose of unlocking the rack R, by releasing the rack lock 68, andpermitting the rack, R to move its full travel or nine teeth.

The rack R is moved in a rearward direction by means of the springs, Rwhich are connected at their rear ends to a bar, R extending between theside members of a bail, 45*, which bail is secured to the shaft R androtates with it. Mounted on the shaft R are a series of hell cranks,

R, having three projecting arms, one projecting forward for the purposeof operating the 0 printing triggers, P, the other arm extendingrearwardly for the purpose of connecting to the link P which serves torotate the type sector P and if the bell crank, R" is rotated about theshaft R the connecting link P will cause the type sector P to rotateabout its center and bring the desired type to the printing line. Thethird arm from the bell crank, R extends in a downward direction andcarries a pin R which engages a vertical 'slot in the lower side of therack, B. so that when the rack R moves forward and backward itcommunicates this motion to the bell crank B through the pin R and whenthe bail 45 is moved to rotate toward the rear or right, in Fig. 14, thespring R which connects the bar R and the bell crank It, tends to movethe'rack R in a rearward direction until this travel is checked by oneof the side of the order plate 60K, rests in small stops K or some otherobstruction to its movement.

The segmental rack, B", mounted on the lower extending arm of the bellcrank, R is for the purpose of obtaining forced alinement of the type onthe sector I? and this alinement segment R is secured firmlyrto thelower arm of the bell crank R. he alinement of the type throu h thesegment R is brought about throng the insertion of the blade R" mountedonthe forward side of the alining frame R which in turn is mounted uponthe shaft R.

The handle, or the motor drive of the machine is adapted to causerotation of shafts 01, R1 and R2, as explained in Ellis No.

Referring to Figs. 11, 12, 13, underneath the keyboard K50, there is a aseries of vertical plates 60K, which tare called order plates. These aresecured to the plates pass down on the left-hand side of the orderplates K, and are held in contact therewith by means of hexagon-headedrivets K23, which as through vertical slots in the plate 601?. Theserivets m, form the stops for the rack R50, and serveas a means ofguiding the keystems K51, to K59, in a vertical direction. Above therivet K23, opposite each of the keystems K51, to K59, there'is anirregular shaped hole in the order plate 60K. Through the u per and ofthis hole, there is inserted a at washer 59K, which has arectan lar slotthrough it, through which the rgstem This washer 59K, is held xedly mthe order plate 60K, and 'ust below it there is a loose washer K99, ofelt, mounted on the keystem, and below this felt washer K99, is a thirdwasher 56K, which is to the keystem and moves with it. Between thewasher 56K, and the bottom of the hole' aforesaid, is a compression-coilspring K80,

the lowerend of which rests against the edge of the hole in the orderplate 60K, and the upper end presses against the washer 56K, mounted onthe keystem. when a keystem is de ressed, it carries down with it thewasher 99, and comp as the ring K80, and when the keystem is rel thespring K80, returns it to its normal position. The order plates 60K arefurther maintained in position by two bars extending horizontally acrosstheir front and rearedges, which bars are marked 61K, and 62K. Thesebars are notched in asuitable fashion to enga e each of the order plates60K, and

is ada slots in the cross bar K3, extendi between the side frames of themachine. cross bars 61K, and 62K, serve also as a means of supportingthe pivots K1, of the latches 52K}; whch holddthe keyatazlms litigateK59, int eir e resse 'tion nrmg' ration of th? machin l These latches ar arranged so that there is one toeach column of nine 'ke stems, andthey swing sidewise from the Swinging about the same pivot 1, are thekeystcm the [80k 106k 68K, and :w I control the keystem latch 52 lost53K,andasringK88,eont :therack lock 68K. e locks 53K, are'olchprovidledin their; rear Iends with a an across ar ,issupported a each of theselocks 58K.

e shiftable bar 65K is provided with a series of notches A adapted tocooperate with the luck latches 53K m a manner which is clearly shown inF 11 and 12.

The operation of e keystem, its latch 52K, its lock 53K and the racklock 63K is set forth in detail ,in Ellis Patent No. 1,197,276.

In Figures 1, 3, and 14, the shaft 01 is shown in normal position, theposition ap- Bearing in Fig. 3 of patent 1,121,270 and ig. 2 of Patent1,203,863. In that position, the abutment of the restoring pin 2 againstthe roller 3 of the crank lever 63K causes the shiftable bar 65K to bemoved toward the right, Fig. 1. It will be understood that Fig. 1 is aview looking toward the rear of the numeral key latching means, coing toF' 12 which is taken from the Ellis Patent the im roved cam lever 63K,168K.

The olding of the parts in the position locks 53K. There is also mountedon the ivot kg,

shown in Figs. 1 and 3 permits the lock latch 4, under the tension ofspring 4, to enter the notch X which is rovided in the extreme eng lpfghe bar 62K be e rams piece appears at r ieces of the su porting framebeing omitted or the sake o clear-noes.

Normally, the lock latches 53K are held out of the downward path oftravel of the studs K25 by the action of the notches A.

When the machine is operated, the shaft 01 the restoring pin 2 from theposition of igs. 1 and 8 to that of Figs. 2 and 4. 2 and 4 re resent theextreme extent o turning of a shaft 01 and the actionsofthe parts whenmovingfrom the normal position of Fi 1 and 3.

The arm 50" which 18 secured to shaft 01 is utilized for "the p ofactuating the latch 4. To that end are is carried by the arm anad'ustable eccentric roller 080 which to wipe inst the latch 4 to shiftt e latch from locking position of Figs. 1 and 3 to the unlockingposition of Figs. 2 and 4 when the shaft ()1 is turned from normalposition to the position appearing in Fig. 4. The first approximate tendegrees of the movementof the "shaft 01 brings about a movement of thekey latches 53K to the position'shown in Fig.2, thereby preventing thekey stems'KSl from being depressed.

Illustration is given only in Figs. 1' and 2 oftwo orders of key stems.the others being omitted for the sake of clearness, as they appear in Fis. 11 and 12'.

In Fig. 2 the right-hand key stem K51 is held in' its depressed positionby its latch plate 52K. Both of the lock-latches 53K have moved in acounterclockwise direction. allowing the bent parts of the latches torest against the sides of the key stems. By reason of the latchingaction, it will be obvious thatno stem which has not alreadybeen'depressed can be depressed once'the bar 65K has been'shifted to theposition s'hown'in Fig. 2 because the lateral parts of the keylatcheswill lie directly under the studs or lugs K25 of 'those 'keystems which have-not been depressed. Y

The various shutter latches 53K for the banks of numeralkeys areoperated the release bar 66K, Figs 11; 12,16 which engages a' 'bellcrank'lever L ,'whioh in turn is operated by a sliding bar L extendingforwardly and rearwardly of the machine,

Figs. 11, 15, 16. In additionthe numeral therolle'r D On'the' returnstroke of the handle O? and the shaft"O,the roller '1) engagingithe hookL which'is pivoted on the slidingba'r L draws the sliding bar Ltowardlthe rear of the machine" and so o'peratesthef'crank L and thetransverse bar 66 releasing the numeral keys." The upward extending armof thehook L ongages a stud L at a "suitable' time to release the hook Lfrom the roller D" and permits the sliding bar L and itsfconnections' tothe transverse slidingbar 66 to resume theirnorm'al position. In theefvent of an overdraft, the keys'which have been depressed are releasedfrom the latch. 52K

at C (Fig. 2) "when the machine i's*p'ut.

' through its cycle'of operations, but these keys are preventedfromrising b the engagement ,of'latch 53K with 'stu K25,*as shown insaid figure and thus remain in operative-position. 7 r The releaseof-the numeral keys when subtraction takes place is done in the'sametime and by the same mechanism that releases the numeral keys' inaddition; r

7 \Vhen a-total or sub-total'is to be taken it is necessaryto r'eleasethe numeral keys during the first fifteen degrees of the forward strokeof the handle 0 and this is accomplished in the following manner. Thetotal and sub-total keys 'K abut at their lower end against a diagonallysliding piece L"- which'sliding piece has a turned over lip nearitsrearupper edge which engagesa stud L on the lower edge' of theirregular shaped piece L. TlllS pieceL 'is pivoted to the lower end ofthe latch L for the repeat key'K and is held in its upper position by asuitable spring. A

second stud L iirtlie lower edge of the piece'L comes underneath asecond hook L pivoted on a downward extension from the piece L and thehook L and the hook and carries down the'piece -L which permits thespring to raisethe hook L until it comes'into engagement with a roller Don-the lower end of a pivoted c'ar'n'"D and thiscam D is in contact witha roller D mounted on theplate D securedtd'the shaft 0 r When the partshave been thusarranged, the initial movement of shaft 01 will causeroller-D32 toswing the cam D63 to the left and-so. movethe hook L64-'and the piece with the overdraftautomatic locking mechanism set forthin myPatent No. 1,508,267 the action of said overdraft locking mechanismwill be clear by reference to Patent No. 1; 508,267, articularly toFigsJB, 9, 10,11, 12

and 13t ereof,xand to F'gs.: 17, 18, 19 and .20 hereof. I

F orthe purpose of locking the bar 6 5K in positionwhere thelock-latches'53K will pregvent the key stemsK51 from being depressed asshown, forinstance, intFigs. 2,8 and 10, there is provided a lockingtrigger 10 which is pivotallymounted in any suitable manner as,'forinstance, atlO on a part of a frame 'rF." This trigger is normally inthe position shown in Fig; 9 but-when the overdraft mechanism of.the'accumulator comes into 'action'on' the occurrence of an overdraft inthe' machine, the bar or link 69L is shifted brings about a position ofthe trigger as shown in Figs. 8 and 10, whereupon the trigger isdisposed so that its bent end constitutes a etc or abutment for the endof the shiftable Bar 65K and prevents said bar from returning to thenormal position shown in Fig. 1 and looks it in the positionshown inFig. 2 where it is impossible for the latch 4 to enter the slot X. Whenthwbar 65K is in this blocked position, the key stem latches 53K areheld so thatthehey stems are locked against depression and "hence theoperator is given a signal that there is an overdraft in theaccumulator. I

i To take care of this condition there is provided a secondary or safetypawl 163K w ich is pivoted at 13 to the lever 63K and is connected to itby a spring 15. The lever 63K and the pawl 163K collectively cooperatewith a pin 14 carried b the barfifiK. The spring 15 normally enab es theparts 63K and 163K to swing as a unit on the 14 but this spring permitsyielding as shown in Fig. 8 when the shifting of the by 65K is blockedby the trigger 10, so that there will be no breakage or interferencewhen the rock shaft 01 turns while the in the bar 65K. I a

%he crank lever and safety part! a pear in detail in Fig. 5, and thetrigger is. s own in detail in Fig. 5A.. I

To'restore the trigger 10 to normal position and to maintain it normallyin the position shown in Fig. 9, there is provided a trigger 10 isblockspririg 10". Y

Normall the parts are in the. position shown in i s. 1 and 3 and thelceystems K51 may be depressed in the difierent banks of the keyboard andthe machine operated in the usual manner as will be clear from the EllisPatents 1,197 .276 and 1,203,863 and i the foregoing disclosure.

The adding and subtracting accumulators of Ellis Patent No. 1,203,863appear in Fig. 14 and the overdraft mechanism therefor 18 shown in Figs.18, 19, 20 in accordance with my Patent N 0. 1,508,267. The keys andmeans setting the respective accumulators for subtraction and for thetaki of totals and sub-totals are shown in F ig i f.

Reference is to be had to Patents L203,863 and 1,508,267 for a fulldisclosure of the accumulators and the manner in which they maybeconditioned for addition, subtraction or the taking of a total orsub-total,-and their cooperation with the racks the parts and mechanismsbeing numbered to correspond with similar parts and5mechanisms in saidpatents.

Particular description, however, will now be given of the overdraftmechanism of my Patent N o.-1,508,267 in order thatithe relationshi ofthe present improved numeral key 100 ring mechanism thereto will fireclear.

ferring first to Figs. 19 and "20, the

former shows theshift bar N90 set to cans:

pressed as. shown in 17, the shift bar N90 is turned to the P0816011.shown in Fig.

19 to block the adding cam hook N and free the subtractin cam hook N56for use.

A link 64L, Fig. 1 which is shifted when subtracting key K67 isdepressed as in said ggure, effects this setting of the shift barReferringnow to Figs. 18, 19, 20.

Pivoted to the order plate 53N of the highest order by a stud N16, is anoverdraft lock latch 66N. A spring 8-1N which cooperates with theoverdraft lock latch 66N andv the order plate 53N, tends to swi theoverdraft lock latch so that its oint willmove in aclockwise direction.his movement is prevented when the shift bar N90 is set for addition asshown in Fig. 14, there being a rounded projection X on the overdraftlock latch which is nessed downwardly by the shift bar N90 when thelatter is set for addition. Con uently when the accumulator is set foraddition as shown in Fig. 14, the pointed and X performs no function.

However, when the shift bar N90 is set forsubtraction, as will be thecase when the subtracting key K67 is do and the machine 0 rated, theturnln of the shift bar N90 mm the position a own in Fig. 14 to theposition shown in Fig. 19, relieves the pressure against the rejectionX" and thereupon the sprin 81 turns the overdraftlock latch 6614 so thatthe int X comes against the rear end of the sua racting pawl or hook N62which arrests it as shown in Fig. 19. The turning of the wheel N50 ofthe highest order either directly .by rack v R50 or b carrying,resulting in an accumulation o subtracted items causes the cam N 56 toengage the tip of the. sub pawl or book N62 by moving from the pos1 tionshown: in Fig. 19 to that shown in 20 thus depressing the left hand endof the subtracting pawl and elevating the right hand end thereof. Thisaction results in the release of int X so that the sp 81N immedia yswings the overdraft latch to the position shown in F 20 whereupon itenga as the rear end of t subtracting pawl or 1: N62 and holds it inthat position until released as hereinafter described. Y

To prevent the balance or total key K63 for the 11 per accumulator andthe sub-total or total posits key K64 from being operated when the upperaccumulator represents an overdrafted condition, means are provided forautomatically locking these keys when this condition prevails, saidmeans being operated from the overdraft shaft N6.

Referring to Figs. 17, 18, there is provided on the left hand end of theshaft N6 a crank N68". Pivoted on the screws L19L of the latches 56L andL56 for the keys K64 and K63, are locks 67 L and 68L whose lower endsare positioned so that they can be engaged with notches 167L in thestems of keys K63, K64, when said keys are in elevated or normalosition. For the purpose of causing the 100 s 67L, 68L, to engage thenotches 167L or to be released therefrom by the turning of overdraftshaft N6, there is rovided an operative connection comprising a link 69Lpivoted to the crank N68 and a link or slide bar 66L pivotally connectedto link 69L at L24L. The link 66L is pivoted to studs L18L on the upperends of the locks 67L, 68L. Near the rear end of the slide bar 66L thereis a slotted part 66L which slides on a pin or stud L20L on the sideframe of the machine, thereby guiding and suspending the bar 66L.Normally the crank N68 is in the position shown in Figs. 17 and 18 evenwhen the subtracting key K67 is depressed.

When an overdraft condition exists in the 11 per accumulator whichcauses the overdraft latch 66N to move to the position shown in Fig. 19,the rocking of the shaft N6 turns the crank N68 backwardly and thereuponthe locks 67L, 68L, are swung so that their lower ends engage thenotches 167L. This results in locking the keys K63 and K64 so that theoperator cannot take a total or sub-total and a signal is thus given,indicating to the operator that the account is overdrawn andnecessitating the manual operation of the decimal slide P67 or suchother means as may be employed to unlock the keys K63, K64.

To release the total and sub-total keys, the hand-operated decimal slideP67 or some other suitable means is provided, said device bein adapted,when operated, to shift the link 73 thereby to rock the crank E60carried by shaft 11 which rocks the arm C which, in turn, rocks crankN68, shifting the link 69L which releases the latches 67L and 68L fromthe total and sub-total keys K63, K64.

\Vhen an overdraft has taken place in the accumulator, the action of theoverdraft mechanism, which will be clear from the foregoing descriptionand the disclosures of my Patent 1,508,267, causes the shifting of thelink 69L from the position shown in Fig. 9 to that shown in Figs. 8 and10, po-

sitioning the trigger 10 in the extreme for-' ward position appearing inFigs. 7 and 10.

While the O1 shaft returns to normal position, the locking trigger 10remains in the position shown in Figs. 8 and 10 where it is directly inthe path of the bar 65K and prevents said bar from returning to normalposition. The pressure of the pin 2 againstthe roller 3, as the shaft 01returns to normal position forces the lever 63K to the position shownbut as the spring 15 yields and as there is nopositive connectionbetween the lever 63K and the pin 14, there is no interference with thelocking action of the locking trigger 10 and the retention of thelock-latches 53K in the locked position shown in Fig. 2.

Finding that the numeral keys cannot be depressed, the operator therebyis given a signal which indicates to him that an overdraft exists in theaccumulator.

By referring to my Patent No. 1,508,267 issued September 9, 1924 onoverdraft key locking and indicating mechanism on page 9, beginning online 28, I mention that when an overdraft has taken place no furtheraddition should be permitted in the accumulator. In the mechanism ofPatent No. 1,508,267, in order to prevent further addition after anoverdraft has taken place, a hook 69L is arranged on the link 69L, thatembraces the stud D21 and renders the credit accumulator inoperativeinsofar as addition is concerned.

With the overdraft key lock mechanism as set forth in my Patent No.1,508,267, it is desirable to prevent further addition after anoverdraft has taken place. On the contrary, with the mechanism of mypresent application for overdraft key locking mechanism it is notdesirable to prevent addition after an overdraft has taken place.Therefore the hook 69L on the link 69L of my Patent No. 1,508,267 isomitted, thus permitting the accumulator to go through its operation asof addition, but as the numeral keys are locked against their depressionno addition is actually performed.

As set forth heretofore, in connection with my present improvements,when an overdraft has taken place in the accumulator, the operatorsattention is called to this condition by the inability to depress any ofthe numeral keys, either for the purpose of addition or subtraction. Theadding key that controls the addition for the credit accumulator is nowdepressed by the operator and the machine is operated, thereby: addingback the exact amount which has caused the overdraft.

Should the mechanism be provided with a key to manually release thedepressed numeral keys, the credit accumulator will go falsely throughits cycle of addition.

It is to be understood that when the credit accumulator is set foraddition, the shift bar N-90 is set as shown in Fig. 9 of my Patent, No.1,508,267, the abutment of the shift bar N-90 against the overdraft locklatch 66--N causing the extreme lower end X1 of the said lock latch66--N to be held away from the backward side of tho subtracting pawlN-62.

When the accumulator is set to 'perform subtraction, the shift bar N--90has been 1 caused to move to assume the position shown in Fig. 19hereof, thus allowin the overdraft lock latch to stop against t esubtracting pawl. Inasmuch as the overdraft lock latch 66N is under thetension of the sprin 81-N as explained in in said patent, sai overdraftlock latch 66- the position shown in Fig. 20 hereof after can overdrafthas taken place, and thro hits train of mechanism causes the balanc ieyor keys to become locked. However, in thepresent application I prefer touse this same initial movement of the lock latch 66-N}to lock thenumeral keys as hereinbefore e lained. When the shift bar N--9O is mo itt eth subtracting position as shown in Fig. 19 hereof, it is latched inthis. sitionl by the latch -N illustrated in Fi s. 3 and 5 of my PatentNo. 1,471,770, Octo r 23,1923.

Assuming that an overdraft has taken place and the operators attentionis called to this fact by being unable to continue with addition orsubtraction of items, for the reason that the numeral keys are lockedagainst depression, the credit-add key is depressed and the machine isoperated; While the machine is going through its cycle the latch 70N isreleased from the path of the shift bar N- b the restoring N49 (Fig. 2,Patent 0. 1,471,770) and the shift bar is permitted to amume its normalposition as shown in Fig. 14 hereofi. The shift bar N--90 forms anabutment the overdraft lock latch 66-N and' f'causes the trigger 10 ofthe present application to assume its normal position as shown it! Figs.7 and 9, thereby removing the lock-latch from the path of the lock stud.K25'in the numeral key stem K-51. I

What I claim is:

1. In a calculating machine, the combin-ation with an accumulatoradapted foreither addition or subtraction, of settable numeral keys onwhich the numbers or amounts which are to be added into, or subtractedThom, the accumulator may be manually set u means adapted toautomatically locking numeral keys which remain undo n to prevent themfrom being 0 re to as up a number after an ove raft has occurred in theaccumulator, and for releasing said locking means.

2. In a calculating machine, the combination with an accumulator adaptedfor hither addition or subtraction, of settablo n keys on which thenumbers or amounts yhich are to be added into, or subtracted from, theaccumulator may be manually set up, means b 0 rations ads operated b theaccumulator adapted to automation y efl'ect locking of the numeral keyswhich-remain undepressed to prevent them from be ngoperated tcset up aafter; an ,overdraft?- has occurred in the accumulator,

coking a 3. In a calculating machine, the combination wit anaccumulatoradapted for either addition or subtraction, of numeral he onwhich the figures or amounts to be added into, or subtracted out of, theaccumulator may be manually set up, locking means which, in the normaluse of the numeral keys, retain the he in set position after saidnumeral keys ave been manually set to enable the amountsor figuresrepresented thereby to be entered into said accumulator, and overdraftmechanism automatically operated when an overdraft occurs in theaccumulator, said overdraft mechanism bemg adapteckwhen thusautomatically operated to mtarfere with the normal action of the lockingmeans aforesaid, thereb to pre vent such numeral he s as have been setfrom being automati y restored and those numeral keys which have notbeen set from bemghmanually operated.

4. a calculat' machine, the combination with the numeral keys thereof onwhich numbers or amounts may be manually set up, of latches for holdithe numeral keys in set tion when said keys have been man iset, meansnormally operated when the mac me 18 going through its cycle of ted toautomatically release t e aforesaid atches so that the numeralkeyswillbefreedfornmtuaman accumulator-adapted for either addition orsubtraction, overdraft v new ads for automatic operation by said accumumwhen an orerdraft occurs, and means operrated by overdraft mechanismadapted for ring with the normal 0 of'the latches, thereby to preventsuch numeralhe as have been set from being automat! y restored and thosenumeral keys which have not been set from being mannally operated,without interfering with an idle operation of the machine.

5. In a calculating machine, the combination with the numeral keysthereof, of latches for holding the muneral keys in set position whensaid keys have been set, means operated when the machine is goingthrough its cycle of operations adapted to release the aforesaidlatches, an accumulator, overdraft mechanism operated by saidaccumulator, a shiftcble bar which determines us whether the latchesshall be arranged to permit depression of the numeral keys, or, toprevent depon of said keys, and a locking trigger which is set by theaction oftheoverdrafttolocksaidbar II.

and means for releasing saidw Ill and maintain the latches in theirlatched position when an ovedraf-t occurs in the accumulator, thereby toprevent depression of any numeral keys which have not been set.

In testimony whereof I afllx my signature.

FREDERICK W. BERNAU.

